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F. G. JOHNSON.

DRBDGING, BXGAVATING, AND GRAPPLING MACHINE. No. 2471.829.

WITNESSES INVENTOB. i

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more powerful and effective and so more use- Y one, two, or all of three ways, viz: first, by p increasing the weight of' the machine; second,

UNITED STATESA FRANK G. JOHNSON, OF

PATENT OFFICE.

BROOKLYN, NEW YORK.

DREDGING, EXCAVATING, AND GRYAPPLING MACHINE.

SPECIFICATION forming part of Letters Patent No. 247,829, dated October 4, 1881.

Application filed February 14, 1881. (No model.)

To all whom it may concern:

Be it known that I, FRANK G. JOHNSON, a citizen of the United States, residing at the city of Brooklyn, in the county of Kings and State of' New York, have invented new and useful ImprovementsinDredging,Excavating, and Grappling Machines, of' which the following is a specification.

My invention relates to the operating of that class of grapplingdredgers, excavators, and buckets the action of which is vertical or downward, and are commonly operated and rendered automatic by the employment of two separate ropes or chains worked by two separate drums and engines, one chain and engine closing, filling, and hoisting the machine, and the other chain and engine opening, emptying, and lowering the same.

The object of' my invention is to simplify the operating of such machines, and render them ful.

The nature of my invention consists in dispensing with one of the chains, drums, and engines and substituting therefor aV cylinder, so attached to the dredger, &c., that the working-arms of the machine, which close it upon its"` work, can be operated by a piston and piston-rod, which are actuated by compressed air, steam, water, or other suitable iiuids or liquids to be supplied to the cylinder by means of a flexible tube.

In order to moge clearly explain the nature, object, and operation of my invention, I will state that the present mode of operating grappling dredgers, excavators, and buckets necessarilydestroys a part of their effectiveness, for the reason that the power applied to close them at the same time lifts them up from the material they are to close upon. To prevent this effect they are usually arranged so as to more or less increase the grappling force by by return ropes or chains, or wheel and axle-5 and, third, by means of a counter-action pole to hold the machine down while it is being closed. Yet when all these means are applied grappling dredgers, excavators, and buckets often fail to till themselves, because the upward draft employed to close them lifts them away from the work before they become filled.

By means of my invention, which l will now describe, the machine isclosed upon its work without any upwardvdraft being applied. accomplish this result by mechanism illustrated in the accompanying` drawings` in which- Figurelis a vertical section 5 Fig. 2, a transverse section through the line a: 0c, Fig. l; and Fig. 3, a transverse section through the line y y, Fig. l.

Similar letters refer to similar parts throughout the several views.

A is a hollow cylinder, O a piston-rod, and B a piston fitted steam-tight within -the cylinder.

f and f are two circular sliding head-plates,

which slide up and down on the sliding and` guiding rods D' and D. The bottom ends of these sliding and guiding rods are fastened into the upper head of the cylinder A. The upper ends of these sliding and guiding rods D and D are held in position by the circular head-plate g g.

To the outer edge of the two sliding headplates fandf are attached by suitable working-joints the working-arms E E of the dredger or excavator. Intothese two plates j' and f is securely and rigidly fastened the top of the piston-rod C. The lower ends of the workingarms E E are suitably fastened by workingjoints to the arms F F, whichcarry the blades or sections of the dredger. The swiveling points of' the dredger, on which its blades or sections work, are on the bottom of the cylinder A, as shown in Fig. 1 at h h. One of the four sliding and guiding rods D' is hollow, being a heavy tube, through which is forced the compressed air, steam, or water to work the piston B. This hollow sliding rod D passes through the upper head of the cylinder A. This hollow sliding rod D also passes up through the-two platesfand f', to form an attachmentf'or the iiexible tube G, through which is forced the compressed air, steam, or water.

d is a two-way cock for turning on and offl the condensed air, steam, or Water.

d is a break in the flexible tube, to show that the cock d may be placed at. any convenient point to be worked.

a is a vent to allow the air to pass out ofand into the cylinder A as the piston B works up and down. The stroke of the piston B is just sufcient to close and open the dredger.

c is the chain or rope employed to lower, hoist, and open the dredger.

The operation of my invention is evident and described brieliy as follows The machine, as represented by Fig. 1, is suspended by the chain or rope c, which holds it open. By this chain or rope c it is lowered to the ground or its work. Vhen thus placed in position the compressed air, steam, or water is let on by turning; the cock ci. The piston B is now forced down by the compressed air, steam, or water unt-il the dredger, excavator, or bucket, whichever it may be, is closed. By the same rope or chain c the dredgcr, excavator, or bucket is now raised in a closed condition, lled, and it is keptfroln opening while it is being` raised by the piston B, being still held down by the compressed air, steam, or water, until the dredger is swung into position to be discharged.

To now open the dredger and discharge its contents it is only necessary to turn the cock d, which will allow the compressed air, steam, or water to pass ont of the cylinder A through the two-way cock d". The weight ofthe dredger and its load, cylinder, and other parts is the opening-power.

I am aware that grappling clam-shell dredgers have been heretofore made which are Worked by steam, air, and water operating a piston within a cylinder directly attached to the dredger, as shown in the two patents granted to T. Symonds, one on April 28, 1874, numbered 150,372, and the other granted on January 8, 1878, and numbered 198,957. Therefore I do not claim, broadly, the application of a piston and cylinder directly attached to grappling-dredgers for operating the same 5 but That I do claim, and desire to secure by Letters Patent, is-

1. ln grappling dredgers, excavators, and buckets, the combination ofthe carrying-arms F F, cylinder A, the workingr or closing arms E E, sliding head-plates j' and f', and pistonrod C, substantially as and for the purgose set forth.

2. In grappling dredgers, excavators, and

buckets, the combination ot' the hollow sliding;l 

